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Articles by Vikyath Ram
Page 3 of 10
How to extract the last n characters from a string using Java?
To extract last n characters, simply print (length-n)th character to nth character using the charAt() method.Examplepublic class ExtractingCharactersFromStrings { public static void main(String args[]) { String str = "Hi welcome to tutorialspoint"; int n = 5; int initial = str.length()-5; for(int i=initial; i
Read MoreUse a character class in Java Regular Expressions
A character class is set of characters that are enclosed inside square brackets. The characters in a character class specify the characters that can match with a character in an input string for success. An example of a character class is [a-z] which denotes the alphabets a to z.A program that demonstrates a character class in Java Regular Expressions is given as follows:Exampleimport java.util.regex.Matcher; import java.util.regex.Pattern; public class Demo { public static void main(String args[]) { Pattern p = Pattern.compile("[a-z]+"); Matcher m = p.matcher("the sky is blue"); System.out.println("The input string ...
Read MoreClass declaration with one method in Java
A class declaration can contain a single method. A program that demonstrates this is given as follows:Exampleclass Message { public void messagePrint() { System.out.println("This is a class with a single method"); } } public class Demo { public static void main(String args[]) { Message m = new Message(); m.messagePrint(); } }OutputThis is a class with a single methodNow let us understand the above program.The Message class is created with a single member function messagePrint(). A code snippet which demonstrates this is as follows −class Message { ...
Read MoreDeriving a Class in Java
A class can be derived from the base class in Java by using the extends keyword. This keyword is basically used to indicate that a new class is derived from the base class using inheritance. It can also be said that it is used to extend the functionality of the class.A program that demonstrates this is given as follows:Exampleclass A { void funcA() { System.out.println("This is class A"); } } class B extends A { void funcB() { System.out.println("This is class B"); } } public class Demo { public ...
Read MoreVariable in subclass hides the variable in the super class in Java
Sometimes the variable in the subclass may hide the variable in the super class. In that case, the parent class variable can be referred to using the super keyword in Java.A program that demonstrates this is given as follows:Exampleclass A { char ch; } class B extends A { char ch; B(char val1, char val2) { super.ch = val1; ch = val2; } void display() { System.out.println("In Superclass, ch = " + super.ch); System.out.println("In subclass, ch = " + ch); } } ...
Read MoreMake a class final in Java
A class can be made final by using the final keyword. The final class cannot be inherited and so the final keyword is commonly used with a class to prevent inheritance.A program that demonstrates a final class in Java is given as follows:Examplefinal class A { private int a = 15; public void printA() { System.out.println("Value of a = " + a); } } public class Demo { public static void main(String args[]) { A obj = new A(); obj.printA(); } }OutputValue of a = 15Now ...
Read MoreConvert a Vector to an array in Java
A Vector can be converted into an Array using the java.util.Vector.toArray() method. This method requires no parameters and it returns an Array that contains all the elements of the Vector in the correct order.A program that demonstrates this is given as follows −Exampleimport java.util.Vector; public class Demo { public static void main(String args[]) { Vector vec = new Vector(); vec.add(7); vec.add(3); vec.add(5); vec.add(2); vec.add(8); Object[] arr = vec.toArray(); System.out.println("The Array elements are: "); ...
Read MoreHow to import all classes in Java?
All the classes in a package can be imported using the import statement along with the character *. For example - All the classes in the package java.util can be imported using import java.util.*;A program that demonstrates this in Java is given as follows:Exampleimport java.util.*; public class Demo { public static void main(String args[]) { Stack stack = new Stack(); stack.push("Apple"); stack.push("Mango"); stack.push("Guava"); stack.push("Pear"); stack.push("Orange"); System.out.println("The stack elements are: " + stack); } }OutputThe stack elements are: ...
Read MoreSwapping Characters of a String in Java
For swapping characters of a string in Java we can use string builder which is mutable so we need not to take care of new object creation during swapping. In this we would create a method which swap characters of string based on location of swapping characters.This method will take location of swapping characters as its parameters.First store both characters need to be swapped and using set character method of string builder swap the targeted characters. Example public class SwapCharacters { public static void main(String[] args) { String str = ...
Read MorePrivate and final methods in Java Programming
In Java private methods are the methods having private access modifier and are restricted to be access in the defining class only and are not visible in their child class due to which are not eligible for overridden. However, we can define a method with the same name in the child class and could access in parent class.Like private methods final methods in Java are the methods having final non-access modifier instead of private and are again restricted to be accessed in the defining class only and are not visible in their child class due to which are not eligible ...
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